class Solution {
    public double myPow(double x, int n) {
        return   n<0?1.0/pow(x,-n):pow(x,n);
    }
    public double pow(double x,int n){
        if(n==0) return 1.0;
        double tmp=pow(x,n/2);
        return n%2==0?tmp*tmp:tmp*tmp*x;
    }
}